All the bartender had to do before going home after last call about a year ago was turn off the lights in the bathroom downstairs.

When she got there, someone was being turned on instead: One of the female performers was orally pleasuring a male performer. They stopped and quickly ran out.

“There are lots of little nooks and crannies and out-of-the-way places you can delve into and hide,” says the 31-year-old bartender about Upright Citizens Brigade East Village theater. She should know: She met her own boyfriend of four years after a show when the two started making out in the box office.

“It was like, ‘Our manager is out of the room, and let’s do this,’ ” says the Williamsburg resident, who asked not to be named.

The community of improvisers and sketch performers at UCB, which operates two theater and school sites in the city, has no shortage of tales of late-night hookups and behind-the-scenes makeout sessions. But members of the ever-growing improv world in New York say the hookup scene is different from your average cabin-fever, high-school hormones situation, because comedians are up for wacky situations and emotional daring.

“When you get a bunch of hilarious, talented, interesting people and you shove them in a theater, day in and day out, people are going to connect with each other,” says Aubrey Plaza, of “Parks and Recreation” and the new film “The To Do List,” who got her start at UCB. “And then you add a s - - tload of alcohol on top of that, and things get crazy.”

The craziest times are, naturally, right after shows.

“The whole back space of the UCB Chelsea theater is just like skeezy hallways with empty kegs and pipes with dripping water,” says Kelly, a 24-year-old Crown Heights resident who’s lived with performers and been a guest at backstage parties, where she’s also seen the occasional oral sex act. (She declined to use her last name so she could talk freely about the hookup scene.) “And then some of the performers bring comedy groupies, a k a improv 100 students, back there.”

The tight-knit community means people get to know each other quickly — but sometimes that backfires.

“You do monologues and stuff, you hear stories about ex-girlfriends and whatnot,” says Jennifer, a 27-year-old who has been involved at UCB for two years (and didn’t want to use her real name to avoid further awkward situations).

Jennifer learned the hard way. Two years ago, she became friendly with a guy in her improv class; the two later joined a team together and started getting intimate. That’s when she found out he was a virgin — and that she had deflowered him.

But that wasn’t the worst part. She got kicked off the improv team she helped form — and she knew it was because of him.

“F - - k the breakup — it really sucks when six people tell you, ‘We don’t want to work with you, we don’t care about you at all,’ ” she says.

But for others, mutual love of comedy can have a happy ending.

Murf Meyer invited his girlfriend, a fellow comedian whom he met through comedy classes, on stage to help him shave his chest, as part of a “first time”-themed episode of the weekly Chris Gethard Show, which started at UCB.

Then another idea hit him: “What the hell, let’s make this memorable,” he thought before proposing to her in front of dozens of audience members and thousands of online viewers.

“I definitely have a flair for the theatrical,” says Meyer, 31, of Red Hook. “We’re both kinda hams. It was something I wanted to share with Chris and the whole community.”